Middle of the night an alarm sounded - we found the oven display showing "F7" - there was no power outage & all LED clocks were working. My wife touched the "Cancel" button and the display returned to normal. There was not heat generated in the device but we are very concerned about this issue. Can't find any references in your Owners Manual which will help us understand the problem nor allow for a night's rest. Please provide some answers to this mystery.